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Finding the Fourth Proportional to 338.20, 507.30 and 81.70

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Solution

The fourth proportional to 338.20, 507.30 and 81.70 is: 122.55

Step by Step Solution

  1. Step 1: Write the proportion equation
    338.20 : 507.30 = 81.70 : x
  2. Step 2: Convert to fraction form
    338.20/507.30 = 81.70/x
  3. Step 3: Cross multiply
    338.20x = 507.30 × 81.70
  4. Step 4: Simplify right side
    338.20x = 41,448.38
  5. Step 5: Solve for x
    x = 41,448.38/338.20
  6. Step 6: Final answer
    x = 122.55

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Why These Related Problems?

These problems maintain the same ratio (1.50) or explore similar proportional relationships. Practicing with related ratios helps build understanding of proportional relationships.